Hydraulically expandable well packer



y Nov. 7, 1967 D. v. CHENOWETH 3,351,349

HYDRAULICALLY EXPANDABLE WELL PACKER Filed oct. 14, 1965 l Elfo. l. y `15in.,

* rre/yex Unit The present invention relates to subsurface well bore apparatus, and more particularly to well packers adapted to be set in well bores.

An object of the invention is to provide a well packer having a normally retracted packing element or packing structure hydraulically expandable against the wall of a surrounding well casing or well bore, the packer having large iiow areas through and around it, and being capable of being run in the well bore and retrieved therefrom in a fast manner, and without effecting inadvertent expansion ofthe packing element or packing structure.

Another object of the invention is to provide a well packer having a normally retracted packing element or packing structure expandable outwardly hydraulically, which is relatively simple in design, rugged, and economical to manufacture.

Another object of the invention is to provide a well packer having a normally retracted packing element or packing structure expandable outwardly in response to iluid press-ure within the packer, the packer being runin and retrieved through use of a tubing spring connected thereto, in which tubing tension or compression does not `adversely aiect the sealing effectiveness of the packing element or structure against the wall of the well bore or casing.

An additional object of the invention is to provide an improved well packer having a normally retracted packing element or packing structure expandable against the wall of a surrounding well casing or well bore by hydraulic pressure, in which pressure can be trapped in the packer to retain its packing element or structure in its expanded condition, and in which the trapped pressure is easily released when retraction of the packing element or structure is desired.

This invention possesses many other advantages, and has other objects which may be made more clearly .apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. lt will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE l is a longitudinal section through a well packer embodying the invention, with its packing element in retracted position;

FlG. 2 is a view similar to FIG. 1 illustrating the packing element of the .packer in its expanded condition sealed against the wall of a surrounding well casing;

FlG. 3 is a partial longitudinal section, on an enlarged scale, illustrating the relieving of the fluid pressure Within the packing element and its return to retracted position.

The well packer A illustrated in the drawings is `adapted to be run in a well casing B on a tubular string C, such as tubing extending to the top of the well bore, and by means of which the packing is lowered in the casing string to the desired location at which it is to be set therewithin. The well packer includes a body structure formed of several parts. An inner central tubular body 1li has its upper box end 11 threadedly secured to the lower end of the tubing string C, this body being threadedly at- States 'Patent assisi-s Patented Nov. 7, 1967 tached to a lower abutment portion 12 of the body structure disposed in longitudinally spaced relation to an upper abutment and gauge ring 13 suitably secured to the upper portion of the body 1d, as by being threaded thereto. Surrounding the lbody between the upper and lower abutments 13, 12 is a packing element or structure 14, of rubiber or rubber-like material, the ends of which are disposed within the downwardly and upwardly facing rims or lip portions 15 ofthe upper abutment 13 and the lower gauge ring portion 16 of the lower abutment, and which sealingly engage the latter. The packing element 14 inherently tends to occupy a retracted position, in which its outer cylindrical surface 17 is of no greater diameter than the external diameters of the upper and lower abutment members 13, 16.

The lower abutment member or gauge ring 16 is threadedly secured to a body sleeve 18 depending therefrom, the lower end of which is, in turn, threadedly secured to a body sub 19 having a lower threaded pin 20 for threaded attachment to a lower device 21, such as a by-pass device illustrated in my patent application for Multiple Zone Injection Apparatus for Well Bores, Ser. No. 492,750, tiled Oct. 4, 1965. This 1oy-pass device (not shown) may have a suitable mechanism therein which permits pressure to be built `up in the fluid in the tubing string C and the interior of the body structure, for the purpose of expanding the packing element 14 outwardly against the wall of the well casing, as described hereinbelow.

The threaded connection 22, 23 between the body 10 and the lower abutment 12 is preferably left-hand. As disclosed, the thickness of the threads is much less than the space or gap between adjoining threads so as to provide a helical path or space 2d between the threads 22, 23 extending from the interior of the packing element 14, to a chamber 25 below the lower abutment ring 16 dened between the lower abutment ring 16 and the sub 19, and between the sleeve 18 and the body 1t) and the sub 19. Initially, the body 10 occupies a lower position within the lower yabutment 12, with its lower end portion 2d, which actually constitutes a valve head, engaging a valve seat 27' .provided by the upper end of the sub 19, the valve head 26 and valve seat 27 being normal to the axis of the well packer. A suitable seal ring 28, such as a rubber `or rubber-like O ring, is disposed in a circular groove 29 in the upper end portion of the sub for sealingly engaging the lower end 26 of the body valve head 26.

When the valve head 26 engages its companion valve seat 27, the upper faces of its threads 22 engage the lower faces of the internal left-hand threads 23 in the lower abutment member 16, which effects a rigid relationship between the body or mandrel 1li and the lower abutment portion 12. At this time, there can be no communication between the central passage 30 through the body structure and the interior ofthe packing element 14, except through a port 31 in the sub 19 opening into the central passage 3i), the upper end of the port opening into an annular space 32 in the sub communicating with a small diameter passage 33 opening into the chamber 25. The upper end of this passage is surrounded by a back pressure valve member 3d, such as a rubber or rubber-like O ring, disposed around the upper portion of the sub and which tends to inherently contract into engagement with the sub and across the upper end of the passage 33 to close the same against return Iiow of fluid from the chamber 25. Fluid can pass upwardly through the passage 33, deecting the back pressure ring or valve element 3ft outwardly, for continued ow into the chamber 25, and for then owing through the helical path 24 between the lower abutment member 16 and body 10 to the interior of the packing element 14. The elastic valve ring 34 will contract against the sub in the region of the upper end of the passage 33, which actually constitutes a valve seat, to prevent the fluid within the packing element 14, helical path 24, and chamber from returning through the passage.

The port 31 may be open at all times, or it may be closed initially by a break-out plug 40 threadedy secured thereto and extending into the passage through the body sub 19. This break-out plug has a passage 41 opening into the sub port 31, the inner end of this passage Ibeing closed by an integral end portion 42 ofthe break-out plug. When the portion of the plug projecting within the passage 30 is broken, the break-out plug being made of frangible material, the inner end of its passage 41 is opened, thereby providing communication between the body and sub passage 3i) and the sub port 31.

Fluid trapped within the packing element 14 can be bled therefrom by rotating the mandrel or body 1t) to the right through the agency of rotating the tubing string C to the right. This will eiect an upward threading of the body 10 with respect to the lower abutment 12 and will elevate its head 26 from the seat 27, thereby establishing communication between the interior of the sub and body passage 30 and the chamber 25, relieving the uid pressure within the packing element 14, and allowing the latter to retract inherently to its initial position. The extent of upward threading of the mandrel or body 10 within the lower abutment 12 is limited by engagement of a split ring mounted in a peripheral groove 46 in the body with the lower end 47 of the lower abutment member 16. When the valve head 26 engages its companion seat 27, as disclosed in FIG. 1, the limit ring 45 is spaced a short distance below the lower end or shoulder 47 ofthe lower abutment.

The parts of the well packer are illustrated in their initial relative positions in FIG. l, in which the breakout plug 40 is also disclosed, although its' use is optional. The well packer A is lowered on the tubing string B in conjunction in a lower apparatus 21, which forms no part of the present invention, to the location in which the packing element 14 is to be expanded and sealed against the wall of the well casing. The iluid passage 30 through the packer A is wide open. There is ample clearance around its exterior, which permits it to be run through the fluid or liquid in the well casing at a comparatively fast rate. During such lowering, pressure cannot be built up that will expand the packing element 14 since the breakout plug 4i) prevents the fluid within the sub and body of the tool from passing to the interior of the packing element 14, which will remain in its retracted position.

When the location in the casing is reached at which the packer is to be set, other mechanism, such as that illustrated in the above application, Ser. No. 492,750, is lowered through the tubing string C to a position below the well packer and suitably secured in place. In passing through the passage 30, it will break the plug 40 and open its passage 41. This other mechanism will enable uid pumped down through the tubing string C to build up a back pressure in the body passage 30 of the tool, which will then pass out through the sub port 31 into its annular space 32, then owing upwardly through the small diameter passage 33 and past the check valve 34 into the chamber 25, continuing around through the helical passage 24 between the lower abutment 16 and body 10 to the interior of the packing element 14, expanding or infiating the latter outwardly against the wall of the well casing, as disclosed in FIG. 2.

The packing 14 will remain in its inflated condition firmly sealed against the wall of the well casing B, even if the pressure within the tubing spring C and the body and sub passage 30 is relieved, since the back pressure valve member 34 will close `across the upper end of the passage 33 and prevent return flow of fluid thereinto from i the packing element 14, helical path 24, and the chamber 25.

With the valve head 26 rmly engaging its seat 27, all of the packer parts, with the exception of the packing element 14 and the back pressure valve ring 34, are iirmly secured to one another. Accordingly, the subjecting of the tubing string C to either tension or compression will result in no relative movement between the packer parts and will not affect the packed-off relation of the packing element against the wall of the well casing. It will remain sealed thereagainst.

In the event the packing element 14 is to be retracted from the wall of the Well casing, the tubing spring C is turned to the right, which will correspondingly turn the mandrel or body 10 and effect itsl upward threading within the lower abutment 12 and its gauge ring 16, elevating the valve head 26 from its companion seat 27 to the extent limited by engagement of the stop ring 45 with the lower end 47 of the lower abutment (FIG. 3). Accordingly, fluid can readily bleed from the interior of the packing element, the space 24 between the helical threads and the chamber 25, through the wide open space 50 between the lower end of the valve head and the seat, to the interior passage 30 of the packer mandrel 10 and its lower sub 19, the packing element 14 retracting inherently to its initial position against the mandrel body, as disclosed in FIG. 3. If desired, the packer A can be removed from the well casing B in a rapid manner by elevating the tubing without any `pressure being built up behind the packing element 14 that might inadvertently expand it against the wall of the well casing.

A desired number of the packers A illustrated can be run in tandem in a single tubing string C for sealing against the wall of the well casing B at desired points therealong. One such potential use is illustrated in the above-identified application Ser. No. 492,750. However, it can also be used separately and back pressure built up therein, as by securing a suitable check valve 6G to the lower end of the packer. As shown, a valve body 61 is threadedly secured to the lower member 21, which has a central passage 62 therethrough. A check valve member 63 moves upwardly against its companion seat 64 to close the passage under the influence of a helical compression spring 65 mounted in a suitable retainer 66 fixed to a pin 67 extending across the valve body 67 and suitably secured thereto, as by welding. The spring 65 exerts a suicient force to lhold the valve ball or element 63 -against its seat 64 as to enable a required pressure to be built up in the body passage 30 of the tool for expanding the packing element 14 outwardly. An increase in the iiuid pressure `suflicient to overcome the force of the spring 65 will then allow uid to discharge through the valve mechanism 60 into the well casing B.

In the event the check valve 60 is used, fluid cannot flow upwardly into the body passage 30 and the tubing string C during lowering of the well packer A through the Well casing. Under these conditions, the break-out plug 40 need not be used and can be omitted, with assurance that no uid pressure will be built up within the interior of the packing element 14 during lowering of the packer in the well bore, the packing element remaining in its retracted position until its setting location is reached. With the back pressure valve 60 being used, the packing element 14 is hydraulically expanded against the wall of the well casing B and is released therefrom in the same manner as described above.

I claim:

1. In a well packer adapted to be lowered in a well bore: body means adapted for connection to a tubular running-in string and having a fluid passage communicable with said tubular running-in string; a hydraulically expandable initially retracted packing structure on said body means; means providing a rst uid path from said passage of said body means to said packing structure lthrough which duid under pressure can be conducted to expand said packing structure; back pressure valve means in said path preventing return flow of fluid from said packing structure through said path to said passage; said body means having a fluid bleeder path from said passage to said first path on the packing structure side of said back pressure valve elements; said body means including relatively movable members; coengageable valve elements on said members closing said bleeder path; and means interconnecting said members whereby rotation of one of said members relative to said other member disengages said valve means and opens said bleeder path.

2. In a well packer as defined in claim l; wherein said packing structure comprises an inflatable packing element; said first path leaning to the interior of said inflatable packing element.

3. In a well packer as dened in claim 1; wherein said interconnecting means comprises an external thread on one member meshing with an internal thread on said other member.

4. In a well packer as defined in claim 2; wherein said interconnecting means comprises an external thread on one member meshing with an internal thread on said other member.

5. In a well packer adapted to be lowered in a well bore: an upper tubular body member adapted for connection to a tubular running-in string and having a central fluid passage communicable with the tubular running-in string; an initially retracted packing element surrounding said body member; an upper abutment on said body member engaging the upper end of said packing element; a lower body structure engaging the lower end of said packing element, said lower structure having a passage communicating with said upper body member passage; said upper body member and lower body member embodying a first fluid path extending from one of said passages to the interior of said packing element and through which fluid under pressure can flow to expand said packing element; back pressure valve means in said first path preventing return flow of fluid from said packing element through said first path to said one of said passages; said body member and body structure p-roviding a bleeder path from one of said passages to said first path on the packing element side of said back pressure valve means; coengageable valve elements on said body member and body structure closing said bleeder path; and means interconnecting said body member and body structure holding said valve elements coengaged, said interconnecting means being of such construction that rotation of said body member relative to said body structure shifts said body member axially of said body structure and disengages said valve elements from each other to open said bleeder path.

6. In a well packer as defined in claim 5; wherein said interconnecting means comprises an external thread on said body member meshing with an internal thread on said Ibody structure.

7. In a Well packer as defined in claim 5; coengageable stop means on said body member and body struc ture for limiting the extent of axial shifting of said body member relative to said body structure.

8. In a well packer as defined in claim 6; coengageable stop means on said body member and body structure for limiting the extent of axial shifting of said body member relative to said body structure.

References Cited UNITED STATES PATENTS 2,791,278 5/1957 `Clark 277-34 X 3,053,322 9/1962 Kline 277-34.6 3,208,532 9/ 1965 Chenoweth 277-34 3,227,462 1/ 1966 Tamplen 277-34 SAMUEL ROTHBERG, Primary Examiner. 

1. IN A WELL PACKER ADAPTED TO BE LOWERED IN A WELL BORE: BODY MEANS ADAPTED FOR CONNECTION TO A TUBULAR RUNNING-IN STRING AND HAVING A FLUID PASSAGE COMMUNICABLE WITH SAID TUBULAR RUNNING-IN STRING; A HYDRAULICALLY EXPANDABLE INITIALLY RETRACTED PACKING STRUCTURE ON SAID BODY MEANS; MEANS PROVIDING A FIRST FLUID PATH FROM SAID PASSAGE OF SAID BODY MEANS TO SAID PACKING STRUCTURE THROUGH WHICH FLUID UNDER PRESSURE CAN BE CONDUCTED TO EXPAND SAID PACKING STRUCTURE; BACK PRESSURE VALVE MEANS IN SAID PATH PREVENTING RETURN FLOW OF FLUID FROM SAID PACKING STRUCTURE THROUGH SAID PATH TO SAID PASSAGE; SAID BODY MEANS HAVING A FLUID BLEEDER PATH FROM SAID PASSAGE TO SAID FIRST PATH ON THE PACKING STRUCTURE SIDE OF SAID BACK PRESSURE VALVE ELEMENTS; SAID BODY MEANS INCLUDING RELATIVELY MOVABLE MEMBERS; COENGAGEABLE VALVE ELEMENTS ON SAID MEMBERS CLOSING SAID BLEEDER PATH; AND MEANS INTERCONNECTING SAID MEMBERS WHEREBY ROTATION OF ONE OF SAID MEMBERS RELATIVE TO SAID OTHER MEMBER DISENGAGES SAID VALVE MEANS AND OPENS SAID BLEEDER PATH. 